乌鲁木齐地区河、库、污水中重金属的化学形态与污染特征

水休中重金属元素的生态效应和运动规律与其存在的形态密切相关。本文研究了该地区主要水系乌鲁木齐河中下游、头屯河、水磨河及位于四宫的乌市排污水中重金属Cd、Zn、Pb和Cu的物理化学形态及其分布特征。应用UV照射分离有机物,ASV法测定,获4元素的总量、悬浮颗粒态、溶解态及溶解态中不稳定态、稳定无机态和稳定有机态的含量。并对这些形态的形成、分配比和分布进行了分析讨论。     

乌江流域水体中不同形态汞分布特征的初步研究

探讨了不同水文季节 (丰水期和枯水期 )乌江河水中汞的赋存形态及其在流域内的时空分布 ,结果表明 :乌江流域表层水体总汞的平均浓度分别为 :丰水期 65 9ng·l- 1 ,枯水期 1 6 6ng·l- 1 .乌江河水汞的主要形态为颗粒态 ,颗粒态汞占总汞的比例为丰水期84% ,枯水期 5 2 % .     

离子色谱／氢化物发生／原子吸收法测定天然淡水中的4种砷形态

首次用国产YSA－Ⅲ型阴离子交换树脂色谱柱,以离子色谱／氢化物发生／原子吸收联用方法,测定天然淡水中４种主要砷形态：亚砷酸盐,砷酸盐,甲基胂酸盐和二甲基胂酸盐。检出限依次为0.28,0.50,0.12和0.18ppbAs,较低于同类方法。实际水样2ngAs/mL加标回收率为93.0％～107.8％。给出几种淡水样中砷形态的分析结果。     

污泥焚烧中Cd形态转化的热力学平衡模拟

采用热力学平衡分析方法,结合典型污泥成分和焚烧条件预测了污泥焚烧过程中重金属Cd的转化和迁移规律。模拟计算中考虑了主量矿物质与Cl、S对Cd的形态转化的影响。研究结果表明,污泥焚烧过程中,在低温的条件下Cd主要以固体碳酸盐形式存在,随着温度升高,碳酸盐分解为固态CdO,随后有气态Cd(OH)2、Cd和CdO生成,并且在较高温度主要以气态Cd存在。焚烧体系中,矿物质SiO2对Cd的形态转化影响大于其他矿物质,SiO2能与Cd结合生成稳定的CdSiO3,从而可有效抑制含Cd气态污染物的排放。焚烧体系中Cl较易与Cd结合形成CdCl2而导致Cd的挥发,Cl含量的增加促进了Cd在焚烧体系中的挥发。在低温阶段,Cd易与S结合形成固态硫酸盐,抑制了金属的挥发;在高温阶段,金属的形态转化基本不受S的影响,但是可以影响气态金属Cd的生成温度。根据污泥在不同焚烧温度、Cl含量、S含量条件下Cd的不同产物形态,可以对Cd的污染进行有效控制。     

硫酸锰渣污染土壤中重金属的形态分布及生物活性

测定了硫酸锰渣污染土壤中Cu,Zn,Cd,Pb,Mn的总量和各形态含量.结果表明重金属总量远超过环境背景值和土壤环境二级标准.重金属各形态分布特征:Cu,有机态>残渣态>铁锰氧化态>碳酸盐态>可交换态;Zn,残渣态>铁锰氧化态>有机态>碳酸盐态>可交换态;Cd,铁锰氧化态>可交换态>碳酸盐态>残渣态>有机态;Pb,铁锰氧化态>残渣态>有机态>碳酸盐态>可交换态;Mn,铁锰氧化态>残渣态>可交换态>有机态>碳酸盐态.重金属的生物可利用性系数和迁移系数均为Cd>Mn>Pb>Cu>Zn.     

Environmental assessment of water-courses of the Turvo Limpo River basin at the Minas Gerais State, Brazil

A study was performed to evaluate the environmental contamination in the Turvo Limpo River basin which receives effluent discharges from domestic (residential and commercial) activities. The watercourses examined were the São Bartolomeu Stream, Turvo Sujo River, and Turvo Limpo River, located in the Minas Gerais State, Brazil. Water samples were collected at the river-side and analyzed for evaluation of pollutant inputs. The pH, temperature, electrical conductivity, redox potential (Eh), dissolved oxygen (DO), total and settleable solids, visual color, hardness, chemical oxygen demand (COD), biochemical oxygen demand (BOD), chloride, total phosphate, total nitrogen, ammonia nitrogen, nitrate, total coliforms and E. coli, as well as the Cd, Pb, Cu, and Zn speciation were determined in the watercourses. The data obtained were compared with those of the Brazilian Environmental Standards and with data from non-contaminated areas. River water characteristics in some sites were far from the limit values established for superficial waters with satisfactory quality. For instance, the BOD values reached 411 mg L^?1 for a maximum limit of 10.0 mg L^?1, while the ammonia nitrogen concentration reached 28 mg L^?1 for a maximum limit of 13.3 mg L^?1. Some sites showed E. coli values above those of non-contaminated regions. Besides the effects of sewage discharges into the water-courses, agriculture activities and the use of the area for cattle husbandry influenced the quality of the river waters, for instance, the pH of a spring-water sample reached the value of 4.3. The São Bartolomeu Stream has been contributing to the deterioration of the water quality of the Turvo Sujo River, while the Turvo Limpo River has also been affected by anthropogenic discharges in the Turvo Sujo River. The speciation of Cd, Cu and Pb showed that these metals were mainly found in the particulate fraction (i. e., associated with the suspended material). Fifty five percent of the water samples showed labile Zn concentrations greater than that of the nonlabile Zn.     

Factor analysis and linear regression model (LRM) of metal speciation and physico-chemical characters of groundwater samples

An approach is described for viewing the interrelationship between different variables and also tracing the sources of pollution of groundwater of north Chennai (India). The data set of 43 variables which include major ions, minor ions and trace metal speciation (Cu, Pb, Cd and Zn) collected during the pre-monsoon and post-monsoon seasons of the year 2000–2001, was subjected to R-mode factor analysis to comprehend the distribution pattern of the said variables. It was found that first factor measures salinity and hardness which explained 19.12% of the total variance (comprised of variables EC, TDS, Na⁺, K⁺, Ca²⁺, Mg²⁺, total hardness, Cl⁻ and SO₄ ²⁻) during pre-monsoon, while it was 25.08% during post-monsoon. The second and third factors were attributed to speciation of zinc and copper ions during both pre-monsoon and post-monsoon. Although there were two more factors, loaded with speciation parameters of lead and cadmium, the variance of them were less than 10%. From this study it is seen that sea water intrusion, municipal solid waste disposal are the identified sources of component of pollution. The importance of metal ions is taking a secondary role and the anthropogenic origin-industrial activity, is the reason in the evaluation of pollution status as they come in the second, third, fourth and fifth factors. As the trace metal speciation was grouped in separate factors, linear regression model (LRM) with correlation analysis was applied to check its validity for prediction of speciation and to apply LRM for rapid monitoring of water pollution.     

The influence of diet on intra and inter-individual variability of urinary excretion of arsenic species in Italian healthy individuals

To study the effect of eating foods with a high arsenic (As) content on the intra and inter-individual variability of urinary concentrations of the As species, daily urine samples were collected for 10 consecutive days from 12 healthy male subjects. A daily food diary was kept throughout the study period. Personal exposure to airborne As was measured once during the study. As³, As⁵, monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and arsenobetaine were determined in all urine samples by inductive coupled plasma mass spectrometry, and the sum of As³ + As⁵ + MMA + DMA (iAs) by hydride generation-atomic absorption spectrophotometry. Exposure to airborne As was below the limit of detection in all samplings. As³ was found in only 19.2% and As⁵ in only 3.3% of the urine samples, whereas high urinary concentrations of arsenobetaine were observed. With the exception of arsenobetaine, expressed as a percentage, a significant inter-individual variability was observed for all species of As, for iAs and for the MMA/DMA ratio (p < 0.001). Instead, the intra-individual variability was significant only for the MMA/DMA ratio (p < 0.001). Among foods with a high As content, only a heavy consumption of seafood was shown to influence inter-individual variability of DMA%, arsenobetaine expressed as μg g⁻¹ creatinine and iAs. In conclusion, even in populations with a high intake of organic As through foods, the finding of a significant inter-individual but no significant intra-individual variability of urinary species confirms the usefulness of urinary As speciation for biological monitoring of exposure to As.     

植物-微生物联合修复石油-重金属复合污染土壤的研究

植物及微生物联合修复石油-重金属复合污染土壤具有很大的潜力。但重金属以不同形态存在关系到石油-重金属复合污染土壤生物修复过程中,植物、微生物的修复效率以及是否需要增加辅助工程解决重金属污染等问题,因此石油-重金属复合污染土壤修复过程中就必须考虑重金属有效态及形态的变化特征。